Can dogs detect cancer?

Cancer sniffing dogs—are they a hoax? Not according to research. A 2011 Japanese study showed that ordinary dogs can be trained to use their sense of smell to detect various kinds of cancer with near-perfect accuracy—even better than any standard medical test for the disease.

The study reported an 8-year-old black labrador was 97 percent accurate in sniffing out colon cancer when she was asked to choose among stool samples doctors collected from 185 patients with and without cancer. In breath samples, she was almost as good at detecting cancer. It didn’t matter whether the patient had early-stage or advanced cancer, the dog was able to accurately detect the samples from cancer patients.

This all suggests, the authors write, that "common scents may exist among various cancer types." Their study appeared in the journal Gut, an affiliate of the British Medical Journal. It didn’t matter if the patients were smokers or not, nor was the dog confused by other factors like infection or inflammation.

When the dog detected the smell of cancer in the samples, she sat down in front of the sample and did not sit when the sample was from a cancer-free patient. Her reward was the chance to play with a tennis ball.

For years, studies have shown that dogs of various breeds and ages can become whizzes at spotting cancer in breath, blood, urine, and tissue samples from patients with lung and breast cancers, ovarian cancer, and bladder cancer.

And further research on ovarian cancer-detecting dogs is currently underway at the University of Pennsylvania’s Working Dog Center, where researchers are training three dogs to sniff out samples that contain ovarian cancer markers. The particularly deadly form of cancer affects about 20,000 women in the U.S. each year and is often not detected in time for treatments to be effective.

So where is all of this going? Should you expect to see a dog in your physician’s office in the near future? That’s not likely, as it would be difficult to have even well-trained dogs in the offices of physicians or in cancer clinics. And the ability to detect scents can vary between dogs and even the same dog on different days, so accuracy is still an issue those involved are working on.

So, what’s next?
Researchers are now trying to figure out exactly what it is the dogs smell. If that can be determined, it could result in electronic equipment that could sniff out cancer as well as, or better than, any dog’s nose and lead to earlier detection of cancer and a brighter outcome for patients—all thanks to man’s best friend.

Written By Corinne Ryan, AAHA Accreditation Coordinator

PenBay Veterinary Associates is a proud member of the American Animal Hospital Association (AAHA). For more information please visit www.penbayvets.com or call 594-8300.